Batraxis minor Wang and Yin

Wang, Dan, Yin, Zi-Wei & Wang, Chun-Xin, 2016, On a collection of Batraxis Reitter (Coleoptera: Staphylinidae: Pselaphinae) from Hainan Island, southern China, Zootaxa 4109 (1), pp. 1-15 : 8-9

6. Batraxis minor Wang and Yin , new species

( Figs 3 B, 5L, 8D–F)

Type material (4 ♂♂, 16 ♀♀). Holotype: CHINA: ♂, labeled ‘ CHINA: Hainan, Ledong Hsien, Jianfengling N.R., Mingfenggu, 18°44'30"N, 108°50'29"E, rainforest, decaying log, 995 m, 26.i.2015, Peng, Yin, Tu, Song, Shen, Zhou, Wang leg.’ Paratypes: CHINA: 1 ♂, 5 ♀♀, same label data as holotype; 2 ♂♂, 7 ♀♀, same data as previous material except ‘ 27.i.2015 ’; 4 ♀♀, same data as previous material except ‘ 23.i.2015 ’.

Diagnosis of male. Body with sparse, minute pubescence in most areas; frons with shallow subantennal transverse sulcus; vertex lacking median pit; antennomeres IX as long as wide; pronotum with shallow median antebasal fovea and basal impression; all tibiae thin; protibiae lacking modifications, mesotibiae without apical spur; protrochanters protuberant ventrally; tergite IV with narrow basal sulcus; discal carinae long, close; with short marginal carinae; aedeagus relatively elongate.

Description. Male ( Fig. 3 B). Body yellowish brown, with sparse, minute pubescence in most areas, length 1.37 mm. Head rectangular, as long as broad, HL = HW 0.32 mm, vertex glabrous, apical margin of frons and clypeus sparsely pubescent; vertex moderately convex, with pair of indistinct vertexal foveae; antennal tubercles low; frons flattened, with shallow subantennal transverse sulcus, lacking vertexal sulcus; each eye composed of about 30 facets; antennae relatively thick, antennomeres III–VII slightly elongate, VIII as long as wide, IX narrower than VIII, X transverse, XI largest, widest near base, then obliquely narrowing toward apex; median gular carina shallow, with two clearly separated distinct gular foveae. Pronotum slightly wider than long, PL 0.27 mm, PW 0.32 mm, with shallow median antebasal fovea and complete basal impression. Elytra wider than long, EL 0.40 mm; EW 0.50 mm, with two pairs of shallow foveae at base. Protrochanters strongly protuberant at ventral margin ( Fig. 5 L). Abdomen wider than long, AL 0.38 mm, AW 0.45 mm, slightly narrowed at base; tergite IV (first visible tergite) sparsely pubescent, with broad, abrupt basal sulcus; discal carinae relatively long, close extending to one-third of tergal length, width between discal carinae 0.11 mm at apices; short marginal carinae extending to apical one-third of tergal length. Aedeagus ( Fig. 8 D–F) 0.24 mm in length, relatively elongate, parameres exceeding apex of median lobe, expanded at apex, each with three preapical setae; endophallus with pair of symmetric sclerites and weakly sclerotized structure connecting them.

Female. Very similar to male in general appearance; protrochanters simple; each eye composed of about 30 facets. Measurements: BL 1.35 mm; HL 0.31 mm; HW 0.32 mm; PL 0.27 mm; PW 0.33 mm; EL 0.41 mm; EW 0.50 mm; AL 0.36 mm; AW 0.47 mm; width between discal carinae of tergite IV 0.10 mm at apices.

Comparative notes. Batraxis minor is unique by the small body size (1.37 mm) and largely reduced subantennal transverse sulcus, when combined with the structure of the aedeagus, this species can be readily separated from all other congeners from Hainan.

Distribution. Southern China: Hainan.

Etymology. The specific epithet refers to the small body size.

Figures

FIGURE 3. Dorsal habitus of Batraxis species. A. B. hainanensis. B. B. minor. Scale line: 0.3 mm.

FIGURE 5. Diagnostic features of male Batraxis species. (A – D. Protibia. E. Mesotibia. F. Mesofemur. G – L. Protrochanter). A, G. B. bicolor. B, F, H. B. tibialis. C, I. B. pilosa. D, E, J. B. spinosas. K. B. hainanensis. L. B. minor. Scale line: 0.1 mm.

FIGURE 8. Aedeagi of Batraxis species. (A, D. in dorsal view. B, E. in lateral view. C, F. in ventral view). A – C. B. hainanensis. D – F. B. minor. Scale line: 0.1 mm.